Poldip2 deletion does not affect Rb expression/phosphorylation.

(A) Immunoblotting was performed using lysates from Poldip2+/+ and Poldip2−/− MEFs in passages 2, 4 and 5. The blots were probed with antibodies against Rb, pRb S780, pRb S807/811, pRb T821, Cdk2, and Cdk4. Densitometry was performed and corrected to β-actin run in parallel (shown in Figure 7A) (B–G). (H) Phosphorylated proteins from Poldip2+/+ and Poldip2−/− cells in passages 2, 4 and 5 were purified with a phosphoprotein binding column. Phosphorylated Rb was measured by immunoblot and normalized to pAkt levels (I). Error bars represent mean ± SEM of 3–4 independent experiments. * P<0.05 comparing Poldip2+/+ with Poldip2−/−.